Ultra-Broadband Bow-tie Antenna

An ultra-broadband bow-tie with a VSWR < 2 from 5 to 60 GHz is revealed. The bow-tie antenna shows frequency independence properties and resonates periodically at multiples of its resonance frequency of 7.7 GHz with the return loss always less than -10 dB. The antenna is linearly polarized and has a maximum directivity of 6 dBi in both the elevation and azimuth planes in the farfield. The antenna is a symmetrical design with straight ends and a flare angle of 90°. It is a simple metal layer on top of a substrate layer which is fed on the metal layer right at the center with closely spaced coplanar striplines. The flare angle and the straight-end of the bow-tie antenna are varied and the 90° straight-end bow-tie antenna is compared with three other bow-tie antennas with flare angle of 60° and round-ends. All four bow-tie antennas have a low VSWR. The E-fields, H-fields and impedance plots of the ultra-broadband bow-tie antenna are shown. The impedance plot is in fact the impedance of frequency independent antennas of 189Ω or 60π across all frequencies.